Well I know how Maura feels about it (obligatory Hi Maura!
). This is ok for a carbine, not much good for anything else; it likely suffers from the same problem as the "interchangeable barrel" uppers- their return to zero is a crapshoot.
Well the folding takedowns get smaller in length than just the upper- even with the upper pins removed you can take off about 1' of length by getting the upper receiver off the barrel. The right barrel and you might be able to get an AR to fit in a shoebox, which is more than can be said for just pulling the pins, but to that end why? Might be easier to transport- I always feel awkward loading rifles into the trunk when I go hunting- I feel like the neighbors judge and I don't want the junkie kid next door knowing I have rifles.